Answer : The mathematical equation used when solving calorimetry problems is:
Explanation :
Calorimetry : It is determining the changes in the energy of a system by measuring the heat transferred with surroundings.
Formula used :
where,
c = specific heat capacity of calorimeter
m = mass of a substance
q = heat required
= change in temperature of substance
Answer : The percent-by-mass concentration of acetic acid is, 5.15 %
Explanation : Given,
Mass of acetic acid = 51.80 g
Density of solution = 1.005 g/ml
Volume of solution = 1.000 L = 1000 ml (1 L = 1000 ml)
First we have to calculate the mass of solution.
Now we have to calculate the percent-by-mass concentration of acetic acid.
Now put all the given values in this formula, we get:
Therefore, the percent-by-mass concentration of acetic acid is, 5.15 %
Answer:
pH ≅ 4.80
Explanation:
Given that:
the volume of HN₃ = 25 mL = 0.025 L
Molarity of HN₃ = 0.150 M
number of moles of HN₃ = 0.025 × 0.150
number of moles of HN₃ = 0.00375 mol
Molarity of NaOH = 0.150 M
the volume of NaOH = 13.3 mL = 0.0133
number of moles of NaOH = 0.0133× 0.150
number of moles of NaOH = 0.001995 mol
The chemical equation for the reaction of this process can be written as:
1 mole of hydrazoic acid react with 1 mole of hydroxide to give nitride ion and water
thus the new number of moles of HN₃ = 0.00375 - 0.001995 = 0.001755 mol
Total volume used in the reaction = 0.025 + 0.0133 = 0.0383 L
Concentration of =
= 0.0458 M
Concentration of =
= 0.0521 M
GIven that :
Ka =
Thus; it's pKa = 4.72
pH ≅ 4.80